I skimmed through it and didn't see much I didn't already know about TypeScript. The only new thing for me was the Assertion Functions - quite neat - could probably use them to make class decorators more type-safe.
Looks like a good introduction to the language for those not familiar with it, but shallower than the "Deep JavaScript" book or even the "JavaScript for impatient programmers" by the same author (those two are for pure JavaScript, but cover pretty advanced topics).